Can I get into iCloud to see my storage from iPhone
Can I check my storage for delete messages from phone to save space and check them in iCloud from phone
iPhone 6s Plus, iOS 13
If you had messages in iCloud turned on Keep all your messages in iCloud - Apple Support and those messages were deleted, then they are permanently gone. If that feature wasn't turned on, you can restore from a backup -- Restore your iPhone, iPad, or iPod touch from a backup - Apple Support.